Re: Factoring exponentials

Okay, I think I know where the problem is in my explanation. I know this is what you are doing Hartlw and I think that this is what you are saying also, Plato. You're actually moving backward, if I'm right. I'm going to give you the whole mess, like I should have in the beginning.

So. I'm trying to find the commutator

where

and thus

Some definitions. k, a, and b are 4-vectors in Minkowski space, and likewise for operators a and b. The 4-vector product is defined as .

We also have the commutators

So on to the commutator:

Using the a and b commutators, integrating over k', and using the 4-vector product to separate the components, for example, we get:

I understand all of this and this is where I took the integrand out. We didn't use because we needed to separate out the 3-vector k to do the last integration over k. The next line should read